One conventional exhaust gas recirculation (EGR) system for compression ignition internal combustion engines uses two actuators. The first actuator creates a pressure differential in the intake passage that draws exhaust gas from the exhaust passage into the intake passage where it mixes with the intake charge. The second actuator regulates the flow rate of exhaust gas in the exhaust passage that is drawn into the intake passage by the first actuator.
Another conventional EGR system employs a single actuator to regulate the flow rate of exhaust gas drawn into the intake passage from the exhaust passage. A stationary throttling device is located in the exhaust passage to promote the flow of exhaust gas into the intake passage. The negative pressure pre-existing in the intake passage created during the intake stroke of the engine provides the pressure differential needed to draw the exhaust gas into the intake passage.